[lovamova]

You can swipe right to get back in Music app and a few more apps. Apple also considered the use of the "Home" button for some "back" actions — back to home screen, back to a recent opened app.

[watty]

This would be great if it were all apps, not just a select few.

[lovamova]

It's Apple's fault for not including it in the iOS HIG. This might be because developers prefer to use swipe gestures for something else entirely.